STEVE MANN sees the world differently to everyone else. For much of his waking day, his view of all that he looks at, the people he meets, and the text he reads comes through a computer screen built into his glasses.

Like the sci-fi characters of the Fifties with their X-ray specs, he wears special eyewear which give him extraordinary powers - allowing him to recognise people he has never met before, see through other people's eyes, and read and write in the dark.

He can also check market prices as he waits for a cab, keep up to date with football scores while he's watching a movie, and send and receive e-mail as he walks to work.

And when he goes shopping, his wife Betty back home can view the store's shelves through his glasses and send him an e-mail to let him know she would like some of that fresh pasta just to the right of the ham.

Steve Mann is a walking computer, a human being in almost perfect harmony with a machine, the nearest thing yet to a Cyborg, that Star Trek man- and-machine combination. While most people are content to have their computer sit on a desktop, or carry it around as a laptop, Professor Mann wants to live in his.

That vest under his shirt, for instance, may look like a regular vest, but it is a 64Mb computer, with the wires and circuitry neatly woven into the strands of the fabric. And his ordinary looking belt has tiny push- button micro-switches that are his keyboard, and that heavy framed pair of glasses he's wearing is really a computer screen.

Instead of looking at the world directly like the rest of us, he looks all day long at computer-generated images taken by sensors on the outside of his glasses and processed by his vest-cum-computer.

"Weird? No, not at all. After you've worn it for a while it seems strange not to have it on. You get used to it," says Professor Mann, the computer guru credited with inventing the wearable computer, a technology seen by many as the next step in the evolution of the computer.

Delegates to an international conference on "wearables" at Fairfax, Virginia, were told that several thousand researchers around the world are now working on wearable projects that they believe will revolutionise everyday life. "Our goal is to offer devices that would be so small and light they could be worn constantly, much as eyeglasses and watches are now, providing access to computing power at all times. It is the age of continuous computing," says Professor Alex Pentland of the Massachusetts Institute of Technology (MIT) Media Lab, a world leader in the development of wearables.

"Build a camera into the frame of your eyeglasses," he enthuses. "And our face-recognition software will help you remember the name of whoever you are looking at by whispering the name in your ear."

And with an array of microphones in your shirt, MIT's word-spotting software would also remind you of important facts. Key the boss's name into the software, for example, and every time someone mentions it, the computer lights up a display on your glasses that tells you what he likes and doesn't like, what his children's names are, when his birthday is, and other data that may be relevant for career enhancement.

According to Dr Chris Baber of Birmingham University, the defining characteristic of a wearable computer is that it allows the wearer the mobility and the freedom to perform other activities while operating it. In essence it becomes an extension of the body, a resource available 24 hours a day. "Wearable computers become part of the wearer's personal space, in much the same way as clothing. In other words, a wearable computer will be continually present unless the wearer takes it off. The wearable computer supports continuous interaction," says Baber, one of Britain's leading experts on wearables.

At the heart of the wearable technology is the integration of computers into smart clothing and personal equipment. Although carrying a portable computer can be more convenient than using a desktop, it still requires conscious effort to use it. The ultimate goal of wearable buffs is to make the connection between computers and humans so seamless it works almost like a real sixth sense.

"When we build computers, cameras, microphones and other sensors into a person's clothes, the computer's view moves from being passive to an active first person vantage point. Smart clothes can be more involved in the user's activities, making them potentially intelligent personal assistants," says Professor Pentland.

Most wearables at present come with either a headset, similar but more discreet than those used in virtual reality games, or with goggles, or modified conventional spectacles. In each case the computer relays data to the screen eye pieces where they can be read. In some cases the messages or graphics are beamed directly at the eye, while in others they are projected a metre in front of the eye on a virtual screen like the head-up display used by pilots.

One of the world leaders in eyepieces, MicroOptical of Boston, has already got the eyeglass down to a tiny box in the corner of one spectacle frame which projects images for the eye to read. Eventually, messages may be beamed directly at the retina.

As with any relatively new technology, the range of applications being developed for wearables is enormous, from helping mechanics to call up layout diagrams in their eye pieces as they work on cars, to surgeons being able to have X-ray images and other data projected in front of their eyes as they operate.

In New York, researchers are working on putting patients records on a wearable - an application that has the potential to improve patient care. "If, for example, you have an injury or a skin or scar mark of some kind which the physician has been monitoring over time, new notes have to be compared each time you go to see if there have been any changes. With our technology, the physicians will not only be able to see in their glasses previous images of what it looked like, they would be able to overlay it on the real patient in front of them to see if there have been any alteration," says Dr Steve Hunt, a research physician at New York University.

At MIT they have already developed a number of wearable devices including jewellery that uses software to recognise people's faces, a brooch that monitors heart beat, and a system that allows deaf-and-dumb people to talk through a synthesiser. One of the problems for deaf people is that although they can communicate in sign language with other deaf people, their carers and a small number of others, communicating with the rest of the population can be a major problem. What the MIT team has done is to design a wearable computer that can recognise the sign language being used by the wearer and translate it into speech. A tiny camcorder mounted in a baseball cap is used for recognition. The work so far has achieved an accuracy of 98 per cent on a 40-word lexicon.

The signs used by the deaf person are first defined for the computer by tracking each unique movement precisely. The software is then programmed and cross refers to a store of sounds that can be converted into recognisable speech. When the program recognises what is being "said" in sign language, it selects the equivalent word and puts it through a synthesiser to be broadcast through a slim speaker mounted in the brim of the cap, allowing the deaf person to "talk" through the synthesiser.

Researchers have also been working on a wearable that may eventually take some of the skill out of snooker. A tiny camcorder mounted onto the player's glasses films the position of the balls and the computer works out the best possible way to hit the cue ball. The recommended route of the cue ball is beamed back onto the player's glasses. "It's pretty simple physics really," says Professor Pentland. "Each possibility is evaluated by the computer to see if it is feasible and its then rated in difficulty depending on how accurate the shot has to be to sink the ball."

Although much current work has been targeted at reducing the size of the eyepiece - down from helmets to goggles and now to glasses - considerable effort is also going into designing new materials that allow the computer itself to be integrated into smart clothing.

At one level MIT has developed a musical jacket, an ordinary denim top that has been transformed into a musical instrument with a keyboard woven from conductive thread. When the thread is touched it sends a signal to another processor which runs a synthesiser disguised as a piece of jewellery.

In another research project, a computer integrated into clothing monitors body temperature and interacts with the room thermostat to keep occupants at the optimum temperature. US defence agencies are also evaluating a smart shirt for soldiers that, in the event of them being injured, will actively help doctors treat their wounds more rapidly. The shirt is woven with sensors and conductive thread that will tell the medics the speed, direction and size of the bullet.

Despite the burgeoning worldwide interest in wearables, Steve Mann at Toronto is still several steps ahead of the pack and has pushed the frontiers of wearables back further than anyone else. " I have been wearing mine for some time. I take it off to sleep and shower, but most other times I have it on," he says. "People get the wrong idea about wearables and they think it is the manifestation of a regular desktop attached to the body, but what we are really talking about is personal imaging or computer supported co-operative imaging."

The outside of his glasses have an array of sensors which act like cameras and absorb and quantify the amount of light coming in and send it to the computer. This data is processed by the computer which sends back the image for Mann to view. The advantage to seeing the world like this is that it is easy to add and display incoming data. "If you passed me in the corridor I would see you on my computer screen, I wouldn't be looking directly at you, but through the medium of the computer. You do get used to it, and the image I get is in real time so I can walk safely across a road wearing it," he says.

Because he has a wireless communication to the outside world, others who are tuned in can communicate with him at all times: "I've had people send me e-mails saying they have recognised people I am talking too," he says. With the wireless connection he has also pioneered one of the more unusual applications of wearable technology which allows he and his wife to have a unique insight into what their partner is doing even when they are miles apart. "If I am shopping at a grocery store my wife can look through my glasses, see what I see and annotate items she wants within my visual field. If she is wearing the equipment too I can see what she sees too," he explains, as he reads another another e-mail looming in front of his eyes. !